Ixion is an optional boss in the Fiend Arena and is stronger than his storyline counterpart. To unlock him, the player must capture and finish the storyline of Machina Striker. This will release Ixion and he can be fought in the Battle Simulator. If all eight aeons are unlocked, the Aeon Cup is unlocked.

Machina Striker can be captured in the Thunder Plains with an L pod once chapter 5 has begun.